You might try Charlie Chandler's Guitar Experience (London, UK). I think he's got a PLEK machine and has for years (there was a name change or a move or something around 2008). He can analyze the thing for you. These "body humps" can be a bit pernicious and sometimes require fret removal, a reshaping of the fretboard and a refret; no guarantees that a simple fret mill will fix this for you. But a run on the PLEK's measuring cycle will tell you more.
No, I did not buy this new. It's from 1991 or there abouts. I think I just got particularly unlucky, that's all.
I appreciate that there is arguments for both truss rod tightening AND loosening. From what I have seen with the guitar, LOOSENING tends to allow a bow up to the 15th fret which means the action can be lowered at the bridge but the high frets are still problematic, whereas TIGHTENING straightens he entire and all frets are "playable" with a slightly lower action available at the bridge.
I am going to take it to a shop soon. Will update then.